This invention relates to a vacuum-type circuit interrupter and, more particularly, to a vacuum interrupter that has exceptional capability for withstanding high voltages.
It is conventional to include in a vacuum interrupter a centrally-located tubular metal shield that surrounds the arcing gap of the interrupter and is capable of intercepting and condensing arcing products before they can reach the insulating housing of the interrupter. Typically, this central shield is electrically isolated from both contacts of the interrupter. It is also conventional to provide the interrupter with end shields at its opposite ends respectively electrically connected to the two contacts of the interrupter for aiding in intercepting and condensing the arcing products. These end shields are electrically isolated from the central shield by vacuum gaps at opposite ends of the central shield. Examples of such vacuum interrupters are shown in U.S. Pat. No. 2,892,912-Greenwood et al. and U.S. Pat. No. 3,441,698-Sofianek, both assigned to the assignee of the present invention.
It has been proposed to provide intermediate shields between the end shields and the central shield to further assist in intercepting and condensing arcing products and also to divide each gap between the central and end shields into series-related gaps. Typically, the resulting series-related gaps collectively have a higher dielectric strength than the larger gaps that they replace. Examples of such interrupters are shown in U.S. Pat. Nos. 3,185,800-Titus and 3,792,214-Voshall.